1. Field of the Invention
The present invention relates to a sealed rectangular battery having a pressure resistance to the internal pressure of the battery despite a simplified structure employed therein and, also, to a battery module using the plurality of sealed rectangular batteries.
2. Description of the Related Art
For the shape of the sealed battery, cylindrical shape has long been widely adopted. In the cylindrical battery, not only can a simplified structure, in which positive and negative electrode plates are wound in a cylindrical form with a separator intervening therebetween, be employed for an electrode assembly, but there is also such an advantage that the pressure resistance to the internal pressure of the battery is excellent.
In recent years, however, having focused on environmental concerns, new type of vehicles such as, for example, automobiles and electric railcars having a secondary battery that is rechargeable incorporated therein has been developed. Where the secondary battery is mounted on a vehicle, the electric power regenerated during the braking can be stored in the mounted battery so that the regenerated electric power can be used as a drive source for the vehicle, thus contributing to an increase of the energy efficiency.